Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin Institute for Medical Systems Biology, Berlin, Germany.
National Institute of Chemistry, Ljubljana, Slovenia.
Nat Commun. 2022 May 18;13(1):2727. doi: 10.1038/s41467-022-30322-7.
The biological role of RNA-binding proteins in the secretory pathway is not well established. Here, we describe that human HDLBP/Vigilin directly interacts with more than 80% of ER-localized mRNAs. PAR-CLIP analysis reveals that these transcripts represent high affinity HDLBP substrates and are specifically bound in their coding sequences (CDS), in contrast to CDS/3'UTR-bound cytosolic mRNAs. HDLBP crosslinks strongly to long CU-rich motifs, which frequently reside in CDS of ER-localized mRNAs and result in high affinity multivalent interactions. In addition to HDLBP-ncRNA interactome, quantification of HDLBP-proximal proteome confirms association with components of the translational apparatus and the signal recognition particle. Absence of HDLBP results in decreased translation efficiency of HDLBP target mRNAs, impaired protein synthesis and secretion in model cell lines, as well as decreased tumor growth in a lung cancer mouse model. These results highlight a general function for HDLBP in the translation of ER-localized mRNAs and its relevance for tumor progression.
RNA 结合蛋白在分泌途径中的生物学作用尚未得到充分证实。在这里，我们描述了人 HDLBP/Vigilin 可直接与超过 80%的 ER 定位 mRNAs 相互作用。PAR-CLIP 分析显示，这些转录本代表了高亲和力的 HDLBP 底物，并特异性地结合在其编码序列 (CDS) 中，与 CDS/3'UTR 结合的细胞质 mRNAs 形成对比。HDLBP 与富含 CU 的长序列强烈交联，这些序列通常位于 ER 定位 mRNAs 的 CDS 中，导致高亲和力的多价相互作用。除了 HDLBP-ncRNA 相互作用组之外，HDLBP 近端蛋白质组的定量分析证实了与翻译装置和信号识别颗粒的成分的关联。HDLBP 的缺失导致 HDLBP 靶标 mRNAs 的翻译效率降低、模型细胞系中的蛋白质合成和分泌受损，以及肺癌小鼠模型中的肿瘤生长减少。这些结果强调了 HDLBP 在 ER 定位 mRNAs 的翻译中的普遍功能及其与肿瘤进展的相关性。
